Resistant hypertension workup and approach to treatment

A genome-wide association study identifies a novel association between SDC3 and apparent treatment-resistant hypertension

BACKGROUND

Compared with patients who require fewer antihypertensive agents, those with apparent treatment-resistant hypertension (aTRH) are at increased risk for cardiovascular and all-cause mortality, independent of blood pressure control. However, the etiopathogenesis of aTRH is still poorly elucidated.

METHODS

We performed a genome-wide association study (GWAS) in first cohort including 586 aTRHs and 871 healthy controls. Next, expression quantitative trait locus (eQTL) analysis was used to identify genes that are regulated by single nucleotide polymorphisms (SNPs) derived from the GWAS. Then, we verified the genes obtained from the eQTL analysis in the validation cohort including 65 aTRHs, 96 hypertensives, and 100 healthy controls through gene expression profiling analysis and real-time quantitative polymerase chain reaction (RT-qPCR) assay.

RESULTS

The GWAS in first cohort revealed four suggestive loci (1p35, 4q13.2-21.1, 5q22-23.2, and 15q11.1-q12) represented by 23 SNPs. The 23 significant SNPs were in or near LAPTM5, SDC3, UGT2A1, FTMT, and NIPA1. eQTL analysis uncovered 14 SNPs in 1p35 locus all had same regulation directions for SDC3 and LAPTM5. The disease susceptible alleles of SNPs in 1p35 locus were associated with lower gene expression for SDC3 and higher gene expression for LAPTM5. The disease susceptible alleles of SNPs in 4q13.2-21.1 were associated with higher gene expression for UGT2B4. GTEx database did not show any statistically significant eQTLs between the SNPs in 5q22-23.2 and 15q11.1-q12 loci and their influenced genes. Then, gene expression profiling analysis in the validation cohort confirmed lower expression of SDC3 in aTRH but no significant differences on LAPTM5 and UGT2B4, when compared with controls and hypertensives, respectively. RT-qPCR assay further verified the lower expression of SDC3 in aTRH.

CONCLUSIONS

Our study identified a novel association of SDC3 with aTRH, which contributes to the elucidation of its etiopathogenesis and provides a promising therapeutic target.

Case Report: Segmental Arterial Mediolysis, a Rare Cause of Hypertension

Rationale:

The differential diagnosis for hypertension with elevated plasma renin is broad. This case illustrates one of the rarer, and therefore underrecognized, causes of high renin hypertension.

Presenting concerns of the patient:

A 41-year-old man with a medical history significant for multiple ischemic strokes and dyslipidemia presented for assessment of decreased renal function and resistant hypertension. His initial workup for secondary causes of hypertension was remarkable for an elevated plasma renin and normal aldosterone. Further investigation with computed tomography (CT) angiography was performed, which demonstrated multiple bilateral renal aneurysms and infarcts.

Diagnoses:

After ruling out other potential causes of bilateral renal aneurysms and infarcts, a diagnosis of segmental arterial mediolysis (SAM) was made.

Interventions:

Optimization of antihypertensive regimen, counseling regarding regular home blood pressure monitoring, and smoking cessation.

Outcomes:

The patient achieved excellent blood pressure control, stable renal function, and had no further strokes or other vascular events.

Teaching points:

Our case demonstrates the importance of considering SAM in the diagnosis of hypertension with elevated plasma renin and as a vasculitis mimic. It also highlights the importance of considering renal vascular imaging in the workup of resistant hypertension.

Black lung persistent pulmonary hypertension of the newborn. Saudi experience with sildenafil and nitric oxide

Objectives:

To determine the clinical presentation, risk factors, diagnosis, and treatment outcome of Saudi infants with black lung persistent pulmonary hypertension of the newborn (PPHN).

Methods:

This is a retrospective review of all neonates with PPHN presented to the Armed Force Hospital Southern Region, Kingdom of Saudi Arabia from January 2012 to December 2014.

Results:

Ten term and near term infants presented with PPHN were included. Maternal diabetes and Down syndrome were the most common identified risk factors for PPHN in the study group. Nine infants were treated with oral sildenafil and did not require mechanical ventilation. Only one infant required mechanical ventilation and inhaled nitric oxide in addition to oral sildenafil.

Conclusion:

Most of the patients in this cohort with PPHN had risk factors, they did not require mechanical ventilation and responded well to oral sildenafil.

Critical Analysis of Cardiovascular and Central Nervous System Fixed Dose Combinations Available in Indian Market

INTRODUCTION

Fixed Dose Combinations (FDCs) are being increasingly used to improve compliance and achieve greater benefits of the two or more active ingredients given together than the corresponding individual drug components given separately.

AIM

To analyse the rationality of Cardiovascular (CV) and Central Nervous System (CNS) FDCs available in Indian market.

MATERIALS AND METHODS

CVS and CNS FDCs, enlisted in Indian Drug Review, 2014, were analysed by a pretested validated eight point criteria tool. Each FDC was assessed for number of active pharmacological ingredients, approval by regulatory authority, listing in WHO Essential Medicine List. While efficacy, safety, pharmacokinetic, pharmacodynamic interactions and advantages of each FDC were analysed by literature search. The total score of the tool was 12 and score ≥7 was considered rational. FDCs were divided in four groups as per rationality and DCGI approval. ANOVA was used for statistical analysis and p<0.05 was considering statistically significant.

RESULTS

Out of 152 FDCs, 107 were CV and 45 belonged to CNS group and 40 had documented evidence of efficacy and safety. Majority of FDCs showed advantage of being convenient by reducing pill count and only 32 showed reducing adverse drug reactions. Out of 107 CV FDCs, 46 were rational and 61 were irrational with a mean rationality score of 6.72±2.82 (CI- 95 %, 3.90 - 9.54). While out of 45 CNS FDCs, 8 were rational and 37 were irrational with a mean rationality score of 6.22±2.08 (CI - 95 %, 4.14 - 8.30). A significant difference in mean rationality score of group A (DCGI approved + rational) was observed as compared to group B (DCGI approved + irrational) and group C (DCGI unapproved + rational) as compared to group D (DCGI unapproved + irrational) (p<0.05).

CONCLUSION

The absence of watertight pre-requisite, critical analysis of the scientific validity of the formulations and 'convenience' category has resulted into proliferation of irrational FDCs. This calls for strict regulatory approval process to avoid miserable FDC scenario in the country.

Treating resistant hypertension: role of renal denervation

Arterial hypertension is the most prevalent risk factor associated with increased cardiovascular morbidity and mortality. Although pharmacological treatment is generally well tolerated, 5%–20% of patients with hypertension are resistant to medical therapy, which is defined as blood pressure above goal (>140/90 mmHg in general; >130–139/80–85 mmHg in patients with diabetes mellitus; >130/80 mmHg in patients with chronic kidney disease) despite treatment with ≥3 antihypertensive drugs of different classes, including a diuretic, at optimal doses. These patients are at significantly higher risk for cardiovascular events, in particular stroke, myocardial infarction, and heart failure, as compared with patients with nonresistant hypertension. The etiology of resistant hypertension is multifactorial and a number of risk factors have been identified. In addition, resistant hypertension might be due to secondary causes such as primary aldosteronism, chronic kidney disease, renal artery stenosis, or obstructive sleep apnea. To identify patients with resistant hypertension, the following must be excluded: pseudo-resistance, which might be due to nonadherence to medical treatment; white-coat effect; and inaccurate measurement technique. Activation of the sympathetic nervous system contributes to the development and maintenance of hypertension by increasing renal renin release, decreasing renal blood flow, and enhancing tubular sodium retention. Catheter-based renal denervation (RDN) is a novel technique specifically targeting renal sympathetic nerves. Clinical trials have demonstrated that RDN significantly reduces blood pressure in patients with resistant hypertension. Experimental studies and small clinical studies indicate that RDN might also have beneficial effects in other diseases and comorbidities, characterized by increased sympathetic activity, such as left ventricular hypertrophy, heart failure, metabolic syndrome and hyperinsulinemia, atrial fibrillation, obstructive sleep apnea, and chronic kidney disease. Further controlled studies are required to investigate the role of RDN beyond blood pressure control.

Treatment strategies for resistant arterial hypertension

BACKGROUND

Resistant hypertension is defined as blood pressure above the target range set by current guidelines despite the concurrent use of three or more antihypertensive drugs of different classes, including a diuretic, at their maximum or highest tolerated doses. This problem affects 5% to 15% of all hypertensive patients and is thus commonly seen by both primary care physicians and specialists.

METHODS

Review of current guidelines and pertinent literature revealed by a selective Medline search.

RESULTS

The treatment of resistant hypertension is multimodal, involving systematic identification of secondary causes of hypertension as well as the exclusion of pseudoresistance (inadequate treatment). Non-pharmacological treatment includes weight loss, dietary salt restriction, exercise, and abstinence from alcohol. Drug treatment consists of an individualized combination of antihypertensive agents with different mechanisms of action. Activation of the sympathetic nervous system is considered to be a major element in the pathogenesis of resistant hypertension; a new interventional treatment, selective denervation of the renal sympathetic nerves, results in clinically relevant and sustained blood pressure reduction in ca. 84% of the patients undergoing the procedure (a mean decrease of office systolic blood pressure by 32 mm Hg and by 12 mm Hg at six months, p <0.001). Among the 206 patients who underwent this procedure in the setting of published studies, 5 had complications; these included pseudoaneurysm of the femoral artery and dissection of the renal artery during the introduction of the ablation catheter.

CONCLUSION

The treatment of resistant hypertension is interdisciplinary and multimodal. The new and promising option of interventional renal sympathetic denervation can be considered for patients whose high blood pressure is inadequately controlled with medication.